Paired Electrosynthesis at Interdigitated Microband Array Electrodes without Intentionally Added ElectrolyteC-C Coupling of Dicyanobenzenes with Methanol

The formation of substituted benzylalcohols from dicyanobenzenes and methanol (C-C coupling) is demonstrated as a model system for paired electrosynthesis and investigated at interdigitated microband array electrodes in a microreactor with/without intentionally added supporting electrolyte. A Pt-Pt microband array with 5 m bands separated by 5 m gaps is employed in dimethylsulfoxide (DMSO) solvent. Yields are optimised to approx. 50% at the point of 100% conversion. The mechanism is investigated by employing isotope labelling (CD3OD, CH3OD, d6-DMSO, 13CH3OH). The methylene group (12C or 13C) is obtained with H2, D2, and DH substitution pattern and a hypothesis for a corresponding mechanism is discussed aided with density functional theory (DFT) calculations. Implication for sustainable electrosynthesis at paired microband electrodes are discussed.